Menopause factsMenopause is defined as the absence of menstrual periods for 12 months. It is the time in a woman's life when the function of the ovaries ceases. The process of menopause does not occur overnight, but rather is a gradual process. This so-called perimenopausal transition period is a different experience for each woman. The average age of menopause is 51 years old, but menopause may occur as early as the 30s or as late as the 60s. There is no reliable lab test to predict when a woman will experience menopause. The age at which a woman starts having menstrual periods is not related to the age of menopause onset. Symptoms of menopause can include abnormal vaginal bleeding, hot flashes, vaginal and urinary symptoms, and mood changes.Complications that women may develop after menopause include osteoporosis and heart disease. Treatments for menopause are customized for each woman.Treatments are directed toward alleviating uncomfortable or distressing symptoms.Menopause is defined as the state of an absence of menstrual periods for 12 months. The menopausal transition starts with varying menstrual cycle length and ends with the final menstrual period. Perimenopause is a term sometimes used and means "the time around menopause." It is often used to refer to the menopausal transitional period. It is not officially a medical term, but is sometimes used to explain certain aspects of the menopause transition in lay terms. "Postmenopausal" is a term used to as an adjective to refer to the time after menopause has occurred. For example, doctors may speak of a condition that occurs in "postmenopausal women." This refers to women who have already reached menopause.

Menopause is the time in a woman's life when the function of the ovaries ceases and she can no longer become pregnant. The ovary (female gonad), is one of a pair of reproductive glands in women. They are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries produce eggs (ova) and female hormones such as estrogen. During each monthly menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a Fallopian tube to the uterus.

The ovaries are the main source of female hormones, which control the development of female body characteristics such as the breasts, body shape, and body hair. The hormones also regulate the menstrual cycle and pregnancy. Estrogens also protect the bone. Therefore, a woman can develop osteoporosis (thinning of bone) later in life when her ovaries do not produce adequate estrogen.

Perimenopause is different for each woman. Scientists are still trying to identify all the factors that initiate and influence this transition period. At what age does a woman typically reach menopause?

The average age of menopause is 51 years old. But there is no way to predict when an individual woman will have menopause or begin having symptoms suggestive of menopause. The age at which a woman starts having menstrual periods is also not related to the age of menopause onset. Most women reach menopause between the ages of 45 and 55, but menopause may occur as earlier as ages 30s or 40s, or may not occur until a woman reaches her 60s. As a rough "rule of thumb," women tend to undergo menopause at an age similar to that of their mothers.

Perimenopause, often accompanied by irregularities in the menstrual cycle along with the typical symptoms of early menopause, can begin up to 10 years prior to the last menstrual period.

Certain medical and surgical conditions can influence the timing of menopause.

Surgical removal of the ovaries

The surgical removal of the ovaries (oophorectomy) in an ovulating woman will result in an immediate menopause, sometimes termed a surgical menopause or induced menopause. In this case, there is no perimenopause, and after surgery, a woman will generally experience the signs and symptoms of menopause. In cases of surgical menopause, women often report that the abrupt onset of menopausal symptoms results in particularly severe symptoms, but this is not always the case.The ovaries are often removed together with the removal of the uterus (hysterectomy). If a hysterectomy is performed without removal of both ovaries in a woman who has not yet reached menopause, the remaining ovary or ovaries are still capable of normal hormone production. While a woman cannot menstruate after the uterus is removed by a hysterectomy, the ovaries themselves can continue to produce hormones up until the normal time when menopause would naturally occur. At this time a woman could experience the other symptoms of menopause such as hot flashes and mood swings. These symptoms would then not be associated with the cessation of menstruation. Another possibility is that premature ovarian failure will occur earlier than the expected time of menopause, as early as 1 to 2 years following the hysterectomy. If this happens, a woman may or may not experience symptoms of menopause.

Cancer chemotherapy and radiation therapy

Depending upon the type and location of the cancer and its treatment, these types of cancer therapy (chemotherapy and/or radiation therapy) can result in menopause if given to an ovulating woman. In this case, the symptoms of menopause may begin during the cancer treatment or may develop in the months following the treatment.

Premature ovarian failure

Premature ovarian failure is defined as the occurrence of menopause before the age of 40. This condition occurs in about 1% of all women. The cause of premature ovarian failure is not fully understood, but it may be related to autoimmune diseases or inherited (genetic) factors.